LONDON, Dec 14 (Reuters) -

Britain's Thames Water said Chris Weston would take over as its new chief executive on Jan. 8, naming the former boss of power equipment rental firm Aggreko to lead a turnaround of the struggling water supplier.

Weston was CEO of Aggreko for seven years until 2021 when the former FTSE 250 member was acquired. Before that he worked for British utility Centrica where he was managing director of international downstream.

He joins Thames Water as it grapples with a highly indebted balance sheet and operational problems which have resulted in a poor environmental performance and angered customers.

Thames Water chairman Adrian Montague said Weston brought the strong operational and strategic expertise that the company needs.

"He has a proven track record working in regulated environments, turning round business performance and improving customer experience," Montague said.

Such is the precarious state of Thames Water's finances, the government was preparing a rescue plan earlier this year in case the company collapsed. It is owned by a Canadian pension fund, British pension funds and other financial investors.

The group launched a latest

turnaround plan

this month designed to get the group back on track within three years.

Its finances remain

under scrutiny

from lawmakers who questioned its interim co-chief executives on Tuesday. They took over in June after the previous CEO quit unexpectedly. (Reporting by Sarah Young; editing by William Schomberg and James Davey)